In the case of laundry washing machines, the washing agent dispenser usually comprises a drawer subdivided into a series of compartments, each of which is destined to be loaded with a dose of detergent and/or additive to be used in a respective phase of the washing program or cycle. The aforesaid drawer is slidably housed in a housing space, defined in the upper part of the machine cabinet and having a hopper-like bottom, a tube connecting the hopper-like bottom with the washing tub.
The drawer is movable between a first position, for loading the desired washer agent or agents, and a second position, for withdrawing the washing agents by means of a flow of water; in the two positions, the drawer is for the most part respectively extracted from or inserted into the respective housing space, the shift from the first to the second position, and vice versa, being conducted manually.
In the withdrawal or working position, each of the compartments of the drawer can be traversed by a flow of water which drives the washing agents into the tub, by means of the aforesaid hopper-like bottom and the respective tube connecting to the tub. Depending on the type of load of the laundry to be washed, the user therefore selects a washing program and places into the various compartment of the drawer the recommended quantities of the required washing agents; at the appropriate time, upon command from the control system (which can be electromechanical or electronic) of the machine, the water to be loaded into the washing tub of the machine is made to transit selectively through each of the various compartments, to drive into the tub the related washing agent; in other words, then, based on the selected program, and depending on the washing phases reached, the control system causes the different washing agents to be withdrawn from the related compartments at the appropriate times.